﻿//
//  Copyright (c) 2009,2010 Liang Quan Qing.
//  All rights reserved.
//
//  Redistribution and use in source and binary forms, with or without
//  modification, are permitted provided that the following conditions
//  are met:
//  1. Redistributions of source code must retain the above copyright
//     notice, this list of conditions and the following disclaimer.
//  2. Redistributions in binary form must reproduce the above copyright
//     notice, this list of conditions and the following disclaimer in the
//     documentation and/or other materials provided with the distribution.
//
//  THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
//  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
//  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
//  ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
//  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
//  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
//  OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
//  HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
//  LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
//  OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
//  SUCH DAMAGE.
//
//

#include <stddef.h>
#include "fastconv.h"
#include "fcnv_config.h"
#include "fcnvlocal.h"

DChar_t MixSurrogate(WChar_t first, WChar_t second, int *pValid)
{
    DChar_t dchar;
    if ( isHighSurrogate(first) )
    {
        if ( isLowSurrogate(second) )
        {
            dchar = SurrogateToDChar(first, second);
            *pValid = 1;
        }
        else
        {
            dchar = first;
            *pValid = 0;
        }
    }
    else if ( isLowSurrogate(first) )
    {
        if ( isHighSurrogate(second) )
        {
            dchar = SurrogateToDChar(second, first);
            *pValid = 1;
        }
        else
        {
            dchar = first;
            *pValid = 0;
        }
    }
    else
    {
        dchar = first;
        *pValid = 0;
    }
    return dchar;
}

size_t fcnv_UTF16ToUTF8(char * dest, const WChar_t * src, size_t srclen, int * pError)
{
    size_t bcount;
    size_t wcount;
    unsigned char utf8buf[8];
    int utf8len, valid, i;
    size_t length;
    DChar_t  dch;
    int error;

    length = srclen ? srclen : (wstrlen(src)+1);

    error = 0;
    for ( bcount = 0, wcount = 0 ; wcount < length ; )
    {
        if ( ! isSurrogate(src[wcount]) )               // if is normal UTF-16 character, not surrogate
        {
            U32CharToU8Buff_1(src[wcount], utf8buf, &utf8len, &valid);
            wcount ++;
        }
        else
        {
            dch = MixSurrogate(src[wcount], src[wcount+1], &valid);
            if ( valid )
                wcount += 2;
            else {
                dch = src[wcount++];
                error = FCNV_ERR_ILLEGAL_CHARS;
            }
            U32CharToU8Buff_1(dch, utf8buf, &utf8len, &valid);
        }
        ///////
        if (dest)
            for ( i = 0; i < utf8len; i++ )
                dest[bcount + i] = utf8buf[i];
        bcount += utf8len;
    }
    if (pError)
        *pError = error;

    return bcount;
}







